The present invention relates to a solid-state image pickup device for transferring charges which are picked up in a pixel-array fashion, thereby obtaining an image signal, and a method of driving the solid-state image pickup device.
In a solid-state image pickup device having plural sensor arrays in one chip (hereinafter referred to as xe2x80x9cCCD sensorxe2x80x9d), a horizontal register for transfer of charges is provided to each sensor array to read out a signal charge picked up at each pixel of the sensor array in a charge-to-voltage converter.
FIG. 1 is a schematic plan view showing the construction of a conventional CCD sensor. That is, the CCD sensor includes sensor arrays e, f, g corresponding to three primary colors of R (red), G (green) and B (blue) for example, and horizontal registers h, i, j, k, l, m, respective two of which are disposed at both sides of each sensor array e, f, g to separately transmit the charges at odd sides and the charges at even sides of the respective pixels of each sensor array e, f, g.
In such a CCD sensor, the charge corresponding to input light is picked up at each pixel of each sensor array e, f, g, and then the charges corresponding to the pixels at the even sides of each sensor array e, f, g are transferred to each horizontal register h, j, l. Thereafter, the charges correspondence to the pixels at the odd sides of each sensor array e, f, g are transferred to each horizontal register i, k, m. After the charges of all the pixels are transferred to the horizontal registers h, i, j, k, l, m, a voltage is successively applied to xcfx86h2 the charges in the horizontal direction. The charges thus transferred is taken out as an output signal by the charge-to-voltage converter (not shown).
In the conventional CCD sensor as described above, however, the distance between the centers of the pixels of each sensor must be several times as large as the sensor size because the charge-transferring horizontal registers are disposed between the respective sensor arrays. Particularly in a CCD sensor for transferring charges while separating the charges between the odd side and the even side, two horizontal registers are disposed between the respective sensors, resulting in further increase of the distance between the centers of the pixels.
For example, in the case of FIG. 1, the interval between the sensor arrays e and f and the interval between the sensor arrays f and g are set to the distance corresponding to 8 lines. Therefore, when an image is picked up, the output signals of the respective sensor arrays which are picked up at the same timing are spatially displaced from one another (in the case of FIG. 1, the displacement amount corresponds to 8 lines), resulting in various disadvantages such as color displacement, etc.
Therefore, in order to avoid such spatial displacements between the output signals of the sensor arrays, it is necessary that a memory is provided at a subsequent stage of the charge-to-voltage converter to temporarily store the output signals in the memory and then take out the output signals, thereby correcting the spatial displacements. However, as the interval between the sensor arrays is increased, the memory capacity to be required is larger, resulting in rise-up of the cost.
The present invention is directed to a solid-state image pickup device and a method of driving the solid-state image pickup device, which have been implemented in order to solve the problem of the related art as described above.
According to a first aspect of the present invention, a solid-state image pickup device comprises image pickup means having a first pixel array and a second pixel array which are disposed so as to be adjacent to each other, and first horizontal charge transfer means disposed so as to be adjacent to the image pickup means, wherein the first horizontal charge transfer means has first and second horizontal charge transfer arrays corresponding to the first and second pixel arrays.
According to a second aspect of the present invention, in the solid-state image pickup device of the first aspect of the present invention, the first and second horizontal charge transfer arrays are disposed so as to be adjacent to the second pixel array in this order, and there is provided vertical charge transfer means for transferring to the first horizontal charge transfer array each charge from each pixel of the first pixel array which is not adjacent to the first horizontal charge transfer array.
According to a third aspect of the present invention, in the solid-state image pickup device of the first aspect of the present invention, the horizontal charge transfer means has two horizontal charge transmission arrays for either of the first and second pixel arrays or each of both the first and second pixel arrays.
According to a fourth aspect of the present invention, in the solid-state image pickup device of the first aspect of the present invention, the image pickup means further includes a third pixel array which is disposed so as to be adjacent to the first pixel array at the opposite side to the second pixel array, and the solid-state image pickup device includes the first horizontal charge transfer means which is disposed so as to be adjacent to the second pixel array of the pixel pickup means and has the first and second charge transfer arrays which are provided in association with the first and second pixel arrays respectively, second horizontal charge transfer means which i disposed so as to be adjacent to the third pixel array of the image pickup means and has a third horizontal charge transmission array provided in association with the third pixel array, and vertical charge transfer means for transferring each charge from each pixel of the first pixel array to the first horizontal transfer array.
According to a fifth aspect of the present invention, in the solid-state pickup device of the fourth aspect of the present invention, each of the first horizontal charge transfer array, the second horizontal charge transfer array and the third horizontal charge transfer array has two horizontal charge transfer arrays which correspond to two different sets of every other pixels in the corresponding one of the first pixel array, the second pixel array and the third pixel array.
According to a sixth aspect of the present invention, a solid-state image pickup device includes: image pickup means comprising a first pixel array, a second pixel array and a third pixel array which are disposed so as to be adjacent to one another in this order; second horizontal charge transfer means comprising two horizontal charge transfer arrays which are disposed so as to be adjacent of the first pixel array and the third pixel array of the image pickup means respectively and correspond to two different sets of every other pixels of the second pixel array respectively; the first horizontal charge transfer means comprising two horizontal charge transfer arrays which are disposed so as to be adjacent to the one horizontal transfer array of the second horizontal charge transfer means which is disposed so as to be adjacent to the first pixel array of the image pickup means, and correspond to two different sets of every other pixels of the first pixel array; third horizontal charge transfer means comprising two horizontal charge transfer arrays which are disposed so as to be adjacent to the other horizontal transfer array of the second horizontal charge transfer means which is disposed so as to be adjacent to the third pixel array of the image pickup means, and correspond to two different sets of every other pixels of the third pixel array; and vertical charge transfer means for transferring the charge from each pixel of the second pixel array of the image pickup means to each of the two horizontal charge transfer arrays corresponding to the second horizontal charge transfer means.
According to a seventh aspect of the present invention, a method of driving a solid-state image pickup device including image pickup means having first and second pixel arrays arranged so as to be adjacent to each other, and horizontal charge transfer means having first and second horizontal charge transfer arrays which are disposed so as to be adjacent to the image pickup means and correspond to at least the first and second pixel arrays respectively, comprises: a first step of picking up the charge at each pixel of the first and second pixel arrays; a second step of transferring charges picked up at some or all of the pixels of the first and second pixel arrays to the corresponding first and second horizontal charge transfer arrays; a third step of successively transferring in the horizontal direction the charges which are transferred to the first and second horizontal charge transfer arrays in the second step.
According to an eighth aspect of the present invention, the solid-state image-pickup device driving method of the seventh aspect of the present invention further comprises a step of transferring to vertical charge transfer means the charges picked up at some or all of the pixels of the first pixel array which is not adjacent to the horizontal charge transfer means after the first step and before the second step, and transferring the charges picked up at some or all of the pixels of the second pixel array to a preceding stage of the second horizontal charge transfer array.
According to a ninth aspect of the present invention, in the solid-state image pickup device driving method according to the seventh aspect of the present invention, some of the pixels of the first and second pixel arrays mean either of odd pixels or even pixels.